Recently, there has been proposed a shutter device in which panels are disposed on the same plane in which they are supported by guide rails, and are disposed in a mutually parallel folded fashion in a state in which they are stowed in a storage box contiguous to one end of the guide rails. Indeed this type of device has advantages, for example, the noise generated during movement of the panels is reduced, the panel width can be made large and a good external appearance is obtained. But, there have been drawbacks, for example, it is difficult to smoothly perform the folding and stowing operation into the storage box and the drawing-out operation, and a complicated driving device is needed in order to ensure smooth operations. Further, it is impossible to immediately become aware of overlapping or squeezing of panels in the guide rails.